using System;
using static System.Math;
using static System.Console;
public class network{

public double[] a,b,w;
public Func<double,double> f;
public readonly int n;

public network(int n, Func<double,double> f){
	this.n=n;
	this.f=f;
	this.a=new double[n];
	this.b=new double[n];
	this.w=new double[n];
	}

public double feed(double x){
	double sum=0;
	for(int i=0;i<n;i++) sum+=w[i]*f((x-a[i])/b[i]);
	return sum;
	}

public void train(double[] xs,double[] ys){
	int ncalls=0;
	var p = new double[3*n];
	Func<vector,double> mismatch=(u)=>{
		ncalls++;
		for(int i=0;i<n;i++){
			a[i]=u[i+0*n];
			b[i]=u[i+1*n];
			w[i]=u[i+2*n];
		}
		double sum=0;
		for(int k=0;k<xs.Length;k++) sum+=Pow(feed(xs[k])-ys[k],2);
Error.Write($"sum={sum}\n");
		return sum/xs.Length;
		};
	for(int i=0;i<n;i++){
		p[i+0*n]=a[i];
		p[i+1*n]=b[i];
		p[i+2*n]=w[i];
	}
	p=simplex.downhill(mismatch,p,step:0.7,minsize:1e-6);
	//p=qnewton.sr1(mismatch,p,1e-3);
	//p=swarm.run(mismatch,start:p,step:0.5,seconds:1,w:0.8);
Error.Write($"ncalls={ncalls}\n");
	}

}//network